It is possible that it's just a loose disk drive cable.

In my experience, that "possible" is about 80% likely. It's an easy fix, but get permission and instructions from Rio Support before cracking the case open to do it, so you don't void your warranty.

A few pointers once you have the case open... you should secure the cables in place with a bit of hot glue. And, assuming you have an IBM TravelStar drive, the hard-drive end of the cable can be incorrectly connected to the drive, offset one pin to the left. This is actually how it looks like it should be connected, but it really goes just as close as possible to the four jumper pins (which are separated by a small gap from the rest of the pins), so close that I don't see how a jumper could even be placed there.

tanstaafl.

"There Ain't No Such Thing As A Free Lunch"